It is known that a sheet conveyance device launches and conveys sheets one by one from a sheet stacking unit that stacks multiple sheets thereon to a skew correction mechanism disposed on a conveyance path to correct skew and further convey the sheet to a prescribed position. Such a skew correction mechanism is generally composed of a pair of registration rollers serving and a pair of conveyance rollers disposed upstream of the pair of registration rollers. The sheet conveyed to the skew correction mechanism is conveyed by the pair of conveyance rollers toward the pair of registration rollers, which stops rotating, so that a leading end thereof abuts a nip formed between the pair of registration rollers. Hence, by continuously driving and bending the sheet with the conveyance rollers after the leading end abuts the nip, skew of the sheet is corrected.
In the conventional sheet conveyance device, the pair of registration rollers stops rotating when the trailing end of the sheet exits therefrom. The leading end of a subsequent sheet then abuts the nip and skew thereof is similarly corrected, after which the sheet is further conveyed. Accordingly, a certain interval between successive sheets must be maintained in order for this arrangement to function as intended, and therefore there is a limit to how much this interval can be shortened after skew correction.
To solve the above-described problem, Japanese Patent No. 2611199 (JP-2611199-B) employs a sheet conveyance device including two sheet conveyance paths each including the above-described skew correction mechanism. In such a system, a sheet is alternately conveyed to the first and second sheet conveyance paths from a sheet stacking unit, so that skew of the sheet is corrected by the first or second sheet conveyance path and is further conveyed toward a third conveyance path.
Hence, since these sheet conveyance paths having the skew correction mechanisms, respectively, are included, a subsequent sheet can be conveyed and the skew thereof is corrected in one of the sheet conveyance paths when the preceding sheet with its skew already corrected is conveyed along the other one of the sheet conveyance paths toward the third conveyance path. Hence, when the trailing end of the preceding sheet exits a pair of registration rollers provided on one of the sheet conveyance paths, skew correction of a subsequent sheet has been completed on the other one of sheet conveyance paths. Accordingly, when the trailing end of the preceding sheet exits the pair of registration rollers on one of the sheet conveyance paths, a subsequent sheet is ready for conveyance toward the third conveyance path. As a result, the interval between successively conveyed sheets can be more minimized after skew correction in comparison with a sheet conveyance device only having a single conveyance path with a skew correction mechanism.
However, according to the sheet conveyance device of JP-2611199-B, since there exist the pair of registration rollers and the sheet conveyance rollers in each of the first and second sheet conveyance paths, a large space is need for these sheet conveyance paths.